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What Eflite Power motor/esc combo for a 13 diameter prop and 10-11 lb plane

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What Eflite Power motor/esc combo for a 13 diameter prop and 10-11 lb plane

Old 03-24-2022, 04:51 AM
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rowdog_14
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Default What Eflite Power motor/esc combo for a 13 diameter prop and 10-11 lb plane

Hello,

I am semi new to the electric build arena. Previously I would just buy what was suggested. I just picked up a plane and want to convert it to electric and there are no real suggestions for the prop I want to use. I had a 15cc gas motor in it and weight was around 12lbs. After taking out all the Gas stuff I am thinking it will be about 10 lbs. I read about the 100w/lb calculations. So I figured a Power 46/52/60 would be best, really the 52/60. still clueless on the ESC needed. I can not have a prop bigger than a 13 diameter. The current prop I have from the Gas motor is a 13x8 MAS and I would like to just reuse that one. I also read I need a watt meter but I am totally in the clouds on what setup I would need. It will be a sport flyer flying off of water and land.

Thanks in advance
Old 03-24-2022, 04:03 PM
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Decided to go with a Power 60 with a castle creation phoenix edge 100
Old 03-25-2022, 12:03 PM
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Originally Posted by rowdog_14 View Post
... I also read I need a watt meter ...
A very long clearance sale, originally 200+$, high quality, now literally peanuts:
Hyperion Emeter II wattmeter with local&remote logging, optical&electrical tach, servo tester - RCG


Without a watt/volt/current/multi-meter you are in the dark.
Until something starts to glow
Prettig weekend Ron
• Without a watt-meter you're in the dark ... until something starts to glow •
• E-flight calculators • watt-meters • diy motor tips&tricks • Cumulus MFC •

Old 03-25-2022, 12:08 PM
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Originally Posted by rowdog_14 View Post
... still clueless on the ESC needed ...
When you know power needed, and have decided upon system voltage, you can calculate max.current
current (in ampθre) = power (in watt) / voltage (in volt)
.
.

It is a good practice to have some headroom built in. Motor runs cooler, slightly more efficient too, and you have some leeway should things go south a bit.
About derating motors, controllers, batteries, electronics in general:

Prettig weekend Ron
• Without a watt-meter you're in the dark ... until something starts to glow •
E-flight calculatorswatt-metersdiy motor tips&tricksCumulus MFC

Last edited by ron_van_sommeren; 03-25-2022 at 12:13 PM.
Old 03-25-2022, 12:12 PM
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I know nothing about good plane/prop/rpm combinations, therefore cannot give you advice about powersystems.


Below an excellent quote about motor selection and powersystem misconceptions
From
brushless motors Kv?.
Originally Posted by scirocco View Post
While an absolutely critical part of the system ...
... Kv is actually the item one should choose last.
  1. Decide your peak power requirement based on the weight of the model and how you want to fly it:
    Magic numbers for modellers.
  2. Pick a preferred cell count (voltage) and pack capacity for how to deliver the power.
  3. Pick a prop that will a) fit on the model and b) fly the model how you want - often as big as will fit is a good choice, but if high speed is the goal, a smaller diameter higher pitch prop will be more appropriate.
  4. Look for a size class of motors that will handle the peak power - a very conservative guide is to allow 1 gram motor weight for every 3 watts peak power.
  5. Then, look for a motor in that weight range that has the Kv to achieve the power desired with the props you can use - a calculator such as eCalc allows very quick trial and error zooming in on a decent choice. For a desired power and prop, you'd need higher Kv if using a 3 cell pack compared to a 4 cell pack. Or for a desired power and cell count, you'd need higher Kv if driving a smaller diameter high speed prop compared to a larger prop for a slow model.
The reason I suggest picking Kv last, is that prop choices have bounds - the diameter that will physically fit and the minimum size that can absorb the power you want. On the other hand, combinations of voltage and Kv are much less constrained - at least before you purchase the components.

So Kv is not a figure of merit, in that higher or lower is better, it is simply a motor characteristic that you exploit to make your power system do what you want, within the constraints you have, e.g. limited prop diameter, if it's a pusher configuration, or if you already have a bunch of 3S packs and don't want to buy more, and so on.

Minor lay-out changes by RvS
61

Last edited by ron_van_sommeren; 03-25-2022 at 03:23 PM.
Old 03-28-2022, 01:03 PM
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Originally Posted by ron_van_sommeren View Post
I know nothing about good plane/prop/rpm combinations, therefore cannot give you advice about powersystems.


Below an excellent quote about motor selection and powersystem misconceptions
From
brushless motors Kv?.

61
Thanks for the info. I will go through it. Definitely sensory overload learning about electrics.
Old 03-29-2022, 08:59 AM
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Don't hesitate to ask questions.

Vriendelijke groeten Ron
• Without a watt-meter you're in the dark ... until something starts to glow •
E-flight calculatorswatt-metersdiy motor tips&tricksCumulus MFC


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